From the viewpoint of burdens of medication administration on patients, an invasive medication such as an intravitreal injection, for example, is desirably a medication which, after administration of a drug into the body, sustained-releases the drug from a site to which the drug is administered, and thereby produces a drug efficacy for a long term. As means for achieving this, hydrogel preparations utilizing self-assembling peptides have been reported.
Patent Literature 1 and Non-Patent Literature 1 disclose a sustained-release preparation for insulin as a water-soluble medication, the preparation using a polypeptide represented by Ac-(Arg-Ala-Asp-Ala)4-CONH2 (SEQ ID NO: 1) as a self-assembling peptide. In addition, Non-Patent Literature 2 discloses a sustained-release preparation using a polypeptide represented by Ac-(Arg-Ala-Asp-Ala)4-CONH2 and containing pindolol, quinine, and timolol maleate as drugs. Here, in the aforementioned literatures, the polypeptide represented by Ac-(Arg-Ala-Asp-Ala)4-CONH2 is PuraMatrix (registered trademark), and PuraMatrix (registered trademark) is also represented by Ac-(Arg-Ala-Asp-Ala)4-NH2. For this reason, PuraMatrix (registered trademark) is referred to as Ac-(Arg-Ala-Asp-Ala)4-NH2 (SEQ ID NO: 1) in the present specification.
However, the sustained-release preparations described in these literatures use only water as a solvent. None of these literatures discloses that an organic solvent selected from the group consisting of polyethylene glycol, dimethyl sulfoxide, glycofurol, and N-methylpyrrolidone is used as a solvent of a pharmaceutical composition comprising a drug and a polypeptide represented by Ac-(Arg-Ala-Asp-Ala)4-NH2, or states that the pharmaceutical composition is useful as a drug sustained-release preparation.